1. Field of the Invention
The present invention relates to a liquid discharge head and an image forming apparatus.
2. Description of the Related Art
As an image forming apparatus such as a printer, a facsimile machine, a copier, a plotter, a multifunction peripheral that includes the respective functions thereof or the like, an inkjet recording apparatus or the like is known as an image forming apparatus of a liquid discharge recording type using a recording head that includes a liquid discharge head discharging a liquid droplet (liquid droplet discharge head), for example.
As the liquid discharge head, there is one using piezoelectric actuators, for example. In the liquid discharge head using piezoelectric actuators, vibration plate members, which form parts of walls of plural pressure generation chambers individually corresponding to plural nozzles which discharge liquid droplets and are arranged in parallel, are deformed by piezoelectric elements (piezoelectric members), the volumes of the respective pressure generation chambers are changed, and liquid droplets are discharged.
In a case of using such piezoelectric actuators, an electrode of each one of the piezoelectric elements is connected with a relay substrate of a carriage via a flexible printed circuit (simply referred to as “FPC”, hereinafter) on which a driving circuit (driver IC) is mounted and a flexible flat cable (simply referred to as “FFC”, hereinafter) (see Japanese Laid-Open Patent Application No. 2011-235560 (Patent reference No. 1)). In this case, a FFC is used to connect the relay substrate of the carriage and a control substrate on which a control part of an apparatus body side is mounted. Thus, signal transfers are achieved for controlling the deformation of the piezoelectric elements for the respective pressure generation chambers by the control part.
Further, as a structure of connecting a FPC and a FFC, for example, it is known to reinforce a solder joint part between the FPC and the FFC by an insulating film for the purpose of positively preventing a circuit pattern near the connection from being disconnected in a case where bending stress is applied near the connection (see Japanese Laid-Open Patent Application No. 2010-027762 (Patent reference No. 2)).
As discussed in Patent reference No. 1, a FFC as a flexible wiring member connecting a liquid discharge head and a relay substrate has flexibility, and thus, it is possible to relatively easily make a layout in a limited narrow space in the carriage by warping or bending it.
However, the FFC receives stress upon being connected with the relay substrate, and also, constantly receives reaction force from the connection (mounting point) even in a connected state in a case where a difference exists between the distance between the head and the connection (mounting point) and the length of the FFC because the length of the FFC may have variation.
Thus, in a case of using as a flexible wiring member a member in which a FFC and a FPC of the side of a head are connected, stress may be applied to a joint between the FFC and the FPC, and damage or a disconnection may occur as a result of cracking occurring near the joint end.